


Mine or No One's

by justanotherbusyfangirl



Category: Supernatural
Genre: Alpha Dean Winchester, Alpha Sam Winchester, Alpha/Beta/Omega Dynamics, Angst, Character Death, Dark, Demon!Dean, Evil Dean Winchester, M/M, Mating Cycles/In Heat, Omega Castiel
Language: English
Status: Completed
Published: 2018-02-27
Updated: 2018-02-27
Packaged: 2019-09-07 17:10:05
Rating: Explicit
Warnings: Major Character Death, No Archive Warnings Apply
Chapters: 1
Words: 477
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16857982
Author URL: https://archiveofourown.org/users/justanotherbusyfangirl/pseuds/justanotherbusyfangirl
Summary: Demon!Dean comes back to be with Castiel during their heat and rut, but he makes some wrong assumptions.





	Mine or No One's

Things were different when Dean was a demon.  He ran away from Castiel, at first out of spite, but then from the joy of running.  All Castiel wanted to do was be with Dean, his Alpha, demon or not.

Sam did his best to keep Castiel happy, his protective Alpha side wanting to make sure his Omega brother-in-law was content.  He helped Castiel nest in Dean’s old room, gave him comfort when needed, and made sure Castiel had the supplies he needed for his upcoming heat.

That’s when Dean showed back up.

Dean’s ruts had lined up with Castiel’s heat long ago, but Castiel had resigned himself to the idea that Dean would find someone else to get him through this rut.  He was excited to see Dean saunter into the bunker, but that excitement was short lived.

“Hey there, Omega.  Ready for a wild ride?” Dean asked, his eyes black.  He cracked his knuckles, scent swarming the room.  Castiel took a step backward when he smelled the sulfur-tinged scent, his mate’s old leather and wood smell altered from the evil inside of him.

“I, uh…” Castiel replied, taking another step backward and running right into Sam.  Sam grabbed Castiel’s shoulders to steady him, seeing Dean for the first time.

“Dean,” Sam said, swallowing, “we didn’t expect you.” The nerves were obvious in his voice.

Dean looked between Sam and Castiel, his eyes flashing pitch black then back to green.  He scented the air, noticing how Sam and Castiel’s scents mingled.  He growled.

“What’s been going on here, Sammy?” he asked, taking a step toward the two of them.  "Taking care of my mate while I’ve been away?“

Sam pushed Castiel to the side, out of Dean’s reach.  He stood to his tallest height, trying to be strong against Dean’s harsh gaze.  "I’ve made sure that Castiel has been safe and happy, or as safe as happy as possible with you gone.”

Dean snapped, lunging at his brother and getting his hands around Sam’s neck.  They fell to the ground, rolling as they fought.  Castiel watched for just a moment until he had had enough.

He grabbed Dean, using the angel strength he had to hold him.  "Stop!“ he yelled, eyes glowing blue.  His heat always drained some of his power, but he was grateful to be able to get Dean off of Sam.  Sam stood, watching the two of them carefully.

"Stop?  So that you can abandon your Alpha, for his brother?” Dean responded, eyes black again.  "No!“

Dean used his combined Alpha and demon strength to break from Castiel’s hold, an angel blade appearing in his hand.  "You’re mine, no one else’s.  If I can’t have you, no one can!”

Castiel couldn’t do anything before Dean lunged, the angel blade piercing his heart.  The last thing he saw was Dean’s black eyes, determined and wild.


End file.
